Loss of balance in humans is known to often result from dysfunction associated with the peripheral vestibular organs of the inner ear. Issues relating to loss of balance can lead to injuries, permanent debilitation and even death.
The vestibular organs define a vestibular system which is central to balance control in humans. The paired vestibular systems or organs are housed within the temporal bone on either side of the head. Each vestibular system includes three orthogonal semicircular canals and two otolith organs known as the utricle and the saccule. Together these elements provide continuous input to the brain about rotational and translational head movement, as well as the detection of gravity. The information allows for the maintenance of retinal image stability and gaze stability via the reflexive eye movement known as the vestibulo-ocular reflex (VOR). The VOR generates compensatory eye movements during sudden head movements to maintain visual stability. For example, if the head pitches nose-down at a velocity of 100° per second, as occurs during running, then during typical viewing (i.e., optical infinity) the eyes are rotated up at the same velocity. The end result is that the angular position of the eyes in space (gaze) remains fixed (i.e., zero gaze velocity), as does the visual image on the retina. Without this reflex eye movement, stable vision becomes difficult or impossible during head movement.
Vestibular dysfunction on one or both sides (unilateral or bilateral) due to age or injury is very common. This dysfunction often results in dizziness, vertigo and imbalance due to disturbances in gaze and postural stability, which can result in reduced mobility and even serious injury due to falls.
Until recently, all systems, programs and devices for vestibular rehabilitation, such as that proposed by Herdman S J, Schubert M C, Das V E, Tusa R J. (2003) (“Recovery of dynamic visual acuity in unilateral vestibular hypofunction” Arch Otolaryngol Head Neck Surg. 129:819-824) can require repetitive lengthy exercises of 40 to 50 minutes per session 4 to 5 times a day to achieve fairly modest functional VOR improvements of on average 5% after 6 to 8 weeks.
Significant improvements in these results have been achieved with the methods and systems proposed in US Patent Application Publication US 2010/0198104 to Schubert et al. and entitled “System for Diagnosis and therapy of gaze stability”. However, the system hardware described in Schubert et al. has limitations in terms of monitoring a patient's actual eye movement during assessment and rehabilitation, measuring and monitoring responses during head movement in planes other than the horizontal plane, and facilitating remote intervention, assessment and program planning by a clinician situated at a location geographically removed from that of the patient.
Similarly, while the described rehabilitation methods appeared to work well for treatment of the damaged side undergoing adaptation, the process appeared to also affect the undamaged untreated side, thereby reducing the overall effectiveness of the treatment in terms of achieving a balanced normal response from both sides.
Further, there is currently no known manner to assess the effectiveness or appropriateness of settings during the exercises.
It is an object of the present invention to provide one or more methods or systems which overcome or ameliorate the deficiencies of the prior art, or which at least offer a useful alternative.